Welcome to the forum. There have been several Ranger swaps over the years so there quite a bit of good info on here. Is your truck 2wd or 4wd? A 4bt weighs around 750 lbs so you need to plan suspension for an engine of that weight. Also, make sure your state doesn't have any EPA rules against the swap. Depending on your power plans you may need heavier axles. The transmission is another consideration. Also, differential gear ratio. The 4bt likes to operate in the 1700-2000 RPM area. Most guys shoot for 1800 which is about where the torque peaks. Your stock engine should be 135 HP with 153 lb ft torque. A bare bones stock 4bt was 105 HP with 265 lb ft torque. Lots of guys like to tune the 4bt for around 200 HP which will have torque near what a big block gas engine has. Doesn't take a lot to get it there. Basically, adjust the injection pump fuel and timing and install a better turbo. You'd also want an intercooler in combo at that power level.